Electrochromic marking systems

ABSTRACT

3-(N-R 2  -N-Acylamino)-7-(N-R 3  -N-R 4  -amino)-10-acylphenothiazines and phenoxazines useful as color formers, particularly in electrochromic recording systems, are prepared by the interaction of the corresponding 3-(N-R 2  -amino)-7-(N-R 3  -N-R 4  -amino)phenothiazinium or phenoxazinium halide with a reducing agent to obtain the corresponding leuco compound and subsequently interacting the leuco compound with at least two molecular proportions of an acylating agent.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

This invention relates to novel compounds classified in the field oforganic chemistry as phenothiazines and phenoxazines, useful ascolor-forming substances, particularly in the art of electrochromicrecording; to electrochromic recording systems containing saidcompounds; and to processes for preparing said compounds.

(b) Information Disclosure Statement

Several classes of organic compounds of widely diverse structural typesare known to be useful as colorless precursors for electrochromicrecording. Among the more important classes, there may be namedleuco-type dyestuffs such as: phthalides, for example, crystal violetlactone, Malachite green lactone; fluorans, for example,3-diethylamino-5,7-dimethylfluoran; and indolinobenzospiropyrans, forexample, 1,3,3-trimethyl-6'-chloro-8'-methoxyindolinobenzospiropyrans.Also utilized as colorless precursors for electrochromic recording,either alone or in admixture with the leuco compounds indicated above,are substances known as redox indicators. The redox indicator whichbecomes colored in situ in the electrochromic recording process also isgenerally a leuco compound. Among the types of compounds which areapplicable as redox indicators are phenothiazines, for example, leucomethylene blue and benzoyl leuco methylene blue. Other specificindicators are Leucoethyl Nile Blue, Leucomethyl Capyrl Blue andLeucosafranine T. Typical of the many such electrochromic recordingsystems taught in the prior art are those described in U.S. Pat. Nos.3,726,769, 3,871,972, 3,864,684, 4,017,366, 4,133,933, and ReissuePatent Re. 29,427 which issued Apr. 10, 1973, Mar. 18, 1975, Feb. 4,1975, Apr. 12, 1977, Jan. 9, 1979, and Oct. 4, 1977, respectively. Themethods for electrochromic recording taught in the prior art have manyvariations. Basically, a sheet of paper is coated or treated on one orboth sides with a coating formulation containing at least one colorlesscolor-forming (leuco) compound. Electrical current is then selectivelyapplied to the coated side of the paper by some means, for example, astylus or a printing head to which an electrical potential can beapplied. The application of the current causes an electrochromicreaction involving the leuco compound to produce a visible imagecorresponding to the design traced by the stylus or that of the printinghead.

The following items to date appear to constitute the most relevant priorart with regard to the instant invention.

U.S. Pat. No. 2,909.520, issued Oct. 20, 1959, discloses compoundshaving the formula ##STR1## in which R is a phenyl or naphthyl moietysubstituted with one or more of the following moieties: alkyl, alkoxy,halo, nitro, haloalkyl, alkoxycabonyl, phenyl, and phenylalkoxy. Thesecompounds are disclosed as being useful as blue color formers incarbonless carbon papers, i.e., carbonless duplicating systems.

Mariga and Oda in Kogyo Kagaku Zasshi 67 (7), 1050-4 (1964) (C.A. 622852b) describe the preparation and properties of acylated methyleneblue having the structural formula ##STR2## in which R represents analkyl or a substituted phenyl moiety. The compounds are disclosed asbeing useful in pressure-sensitive carbonless duplicating systems.

U.S. Pat. No. 4,309,255, issued Jan. 5, 1982, discloses and claims aphenothiazine having the structural formula ##STR3## which is disclosedas being useful as a blue color former in electrochromic recordingpaper.

Smets and Simionescu in Makromolecular Chemistry 1977 178(9), 2719-23(C.A. 87 186052t) disclose as a monomer for a colored polymerN-acryloyl-N,N',N'-trimethylthionine having the formula ##STR4##

Japanese Patent Publication No. 80,040,798, published Mar. 22, 1980,discloses thionines having the structural formula ##STR5## in which R₁and R₂ represent hydrogen or methyl; R and X represent halogen; Zrepresents (CH₂)₃ to 12; n represents zero or one; m represents one ortwo; and m+n equals two. The compounds are disclosed as being monomersfor reaction with polyethyleneimine to obtain a green-blue solid whichis swellable by water and N,N-dimethylformamide.

SUMMARY OF THE INVENTION

In its composition of matter aspect, the invention relates to certain3-(N-R² -N-acylamino)-7-(N-R³ -N-R⁴ -amino)-10-acyl-phenothiazines andphenoxazines useful as colorless precursors in electrochromic recordingsystems.

The present invention provides in its article of manufacture aspect, asubstrate for use in electrochromic recording systems comprising asupport sheet containing as a color-forming substance 3-(N-R²-N-acylamino)-7-(N-R³ -N-R⁴ -amino)-10-acyl-phenothiazines andphenoxazines.

In its process aspect, the invention relates to a process for producing3-(N-R² -N-acylamino)-7-(N-R³ -N-R⁴ -amino)-10-acyl-phenothiazines andphenoxazines which comprises interacting the corresponding 3-(N-R²-amino)-7-(N-R³ -N-R⁴ -amino)phenothiazinium or phenoxazinium halidewith a reducing agent to obtain the corresponding leuco compound andsubsequently interacting the leuco compound with at least two molecularproportions of an acylating agent.

DETAILED DESCRIPTION INCLUSIVE OF THE PREFERRED EMBODIMENTS

More specifically, this invention in its composition of matter aspectresides in the novel compounds having the structural formula ##STR6##wherein R and R⁵ independently represent non-tertiary C₁ to C₄ alkyl,non-tertiary C₁ to C₄ alkoxy, halogen or nitro; R¹ represents hydrogen,non-tertiary C₁ to C₁₂ alkyl, C₄ to C₈ cycloalkyl, non-tertiary C₁ toC₁₂ alkyl substituted by halogen, non-tertiary C₁ to C₄ alkoxy ornon-tertiary C₁ to C₄ alkoxycarbonyl, phenyl, phenyl substituted by oneto three of non-tertiary C₁ to C₄ alkyl, non-tertiary C₁ to C₄ alkoxy,nitro, halo, phenyl, cyano or trihalomethyl; R² represents hydrogen,non-tertiary C₁ to C₄ alkyl, phenyl, phenyl substituted by one or two ofhalo, nitro, non-tertiary C₁ to C₄ alkyl or non-tertiary C₁ to C₄alkoxy, benzyl or benzyl substituted in the benzene ring by one or twoof halo, nitro, non-tertiary C₁ to C₄ alkyl or non-tertiary C₁ to C₄alkoxy; R³ and R⁴ represent hydrogen, non-tertiary C₁ to C₄ alkyl,phenyl, phenyl substituted by one or two of halo, nitro, non-tertiary C₁to C₄ alkyl or non-tertiary C₁ to C₄ alkoxy, benzyl or benzylsubstituted in the benzene ring by one or two of halo, nitro,non-tertiary C₁ to C₄ alkyl or non-tertiary C₁ to C₄ alkoxy; and Xrepresents S or O.

Particular embodiments within the ambit of the composition of matteraspect are the novel 1/2-R-3-[N(R¹ -CO)-N-R² -amino]-7-(N-R³ -N-R⁴-amino)-8/9-R⁵ -10-(R¹ -CO)-phenothiazines of Formula I wherein X is Shaving the formula ##STR7## in which R, R¹, R², R³, R⁴ and R⁵ have thesame respective meanings given in Formula I.

Other particular embodiments with the ambit of the composition of matteraspect are the novel 1/2-R-3-[N-(R¹ -CO)-N-R² -amino]-7-(N-R³ -N-R⁴-amino)-8/9-R⁵ -10-(R¹ -CO)-phenoxazines of Formula I wherein X is Ohaving the structural formula ##STR8## in which R, R¹, R², R³, R⁴ and R⁵have the same respective meanings given in Formula I.

In its process aspect, the invention sought to be patented resides inthe process for preparing a compound according to Formula I having thestructural formula ##STR9## which comprises in the first stepinteracting a compound having the structural formula ##STR10## with areducing agent to obtain the corresponding leuco compound having thestructural formula ##STR11## and in a second step, interacting the leucocompound with at least two molecular proportions of an acylating agenthaving the structural formula

    R.sup.1 --CO--Z                                            Formula VI

in which Z represents halo or R¹ COO and R, R¹, R², R³, R⁴ and R⁵ havethe same respective meanings given in Formula I.

In its article of manufacture aspect, the invention sought to bepatented resides in a substrate for use in electrochromic recordingcomprising a support sheet containing as a color-forming substance aphenothiazine or phenoxazine having the structure of Formula I.

A particular embodiment within the ambit of the article of manufactureaspect in the substrate for use in electrochromic recording comprising asupport sheet containing as a color-forming substance a 1/2-R-3-[N-(R¹-CO)-N-R² -amino]-7-(N-R³ -N-R⁴ -amino)-8/9-R⁵ -10-(R¹-CO)-phenothiazine of Formula II wherein R, R¹, R², R³, R⁴ and R⁵ havethe same respective meanings given in Formula II.

In a second particular embodiment within the ambit of its article ofmanufacture aspect is the substrate for use in electrochromic recordingcomprising a support sheet containing as a color-forming substance a1/2-R-3-[N-(R¹ -CO)-N-R² -amino]-7-(N-R³ -N-R⁴ -amino)-8/9-R⁵ -10-(R¹-CO)-phenoxazine of Formula III wherein R, R¹, R², R³, R⁴ and R⁵ havethe same respective meanings given in Formula III.

As used herein the terms "non-tertiary C₁ to C₄ alkyl" and "non-tertiaryC₁ to C₁₂ alkyl" denote saturated monovalent straight or branchedaliphatic hydrocarbon radicals including methyl, ethyl, propyl,isopropyl, butyl, isobutyl, amyl, 1-methylbutyl, 3-methylbutyl, hexyl,isohexyl, heptyl, isoheptyl, octyl, isooctyl, 2-ethylhexyl, nonyl,3-ethylheptyl, n-decyl, n-undecyl, n-dodecyl and the like.

The term "non-tertiary C₁ to C₄ alkoxy" includes saturated acyclic,straight or branched-chain groups such as methoxy, ethoxy, propoxy,isopropoxy, butoxy, sec-butoxy and isobutoxy.

As used herein the terms "halo" and "halogen" include chloro, fluoro,bromo and iodo. Chloro is the preferred halo substituent because of therelatively low cost and ease of preparation of the requiredchloro-substituted intermediates and because the other halogens offer noparticular advantages over chloro. However, the other above-named halosubstituents are also satisfactory.

As used herein the term "C₄ to C₈ cycloalkyl" denotes saturatedmonovalent cyclic aliphatic hydrocarbon radicals including cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and the like.

The phenothiazinium and phenoxazinium dyes which are used asintermediates or starting materials for the compounds of Formula I aregenerally known dyestuffs readily prepared by procedures well known inthe dyestuff art. Four references to the preparation of thephenothiazine and phenoxazine dyestuffs are: (a) Journal of the Societyof Dyers and Colourists 4, 39 (1888); (b) Liebig's Annalen der Chemie251, 1 (1889); (c) Chemische Berichte 25, 3128 (1892); (d) FIAT FinalReport No. 1313 and PB Report 85172, Vol. II, p. 372.

The acylating agents of Formula VI may be either aliphatic acidanhydrides (Z=R¹ COO) or acid halides (Z=halo, preferably chloro), bothof which constitute well known classes of compounds many of which arecommercially available or are readily obtained by conventional synthesiswell known in the art. The following list exemplifies aliphatic acidanhydrides and acid halides useful in carrying out the processes of thisinvention. Acetic anhydride, chloroacetic anhydride, dichloroaceticanhydride, trifluoroacetic anhydride, propionic anhydride, butyricanhydride, isobutyric anhydride, valeric anhydride, hexanoic anhydride,hepanoic anhydride, acetyl bromide, acetyl chloride, acetyl fluoride,bromoacetyl bromide, bromoacetyl chloride, chloroacetyl chloride,methoxyacetyl chloride, propionyl chloride, 2-bromopropionyl chloride,3-bromopropionyl chloride, 2-chloropropionyl chloride, 3-chloropropionylchloride, butyryl chloride, 4-chlorobutyryl chloride, 2-ethylbutyrylchloride, isobutyryl chloride, valeryl chloride, 5-chlorovalerylchloride, isovaleryl chloride, 4-methylvaleryl chloride, hexanoylchloride, 6-bromohexanoyl chloride, heptanoyl chloride, octanoylchloride, nonanoyl chloride, decanoyl chloride, 10-undecanoyl chloride,palmitoyl chloride, myristoyl chloride, lauroyl chloride, cyclopropylcarboxylic acid chloride, cyclobutane carboxylic acid chloride,cyclohexyl carboxylic acid chloride, m-anisoyl chloride, p-anisoylchloride, benzoyl bromide, benzoyl chloride, benzoyl fluoride,4-biphenylcarbonyl chloride, 2-bromobenzoyl chloride, 4-bromobenzoylchloride, 4-butoxybenzoyl chloride, 4-butylbenzoyl chloride,2-chlorobenzoyl chloride, 3-chlorobenzoyl chloride, 4-chlorobenzoylchloride, 4-cyanobenzoyl chloride, 2,4-dichlorobenzoyl chloride,2,6-dichlorobenzoyl chloride, 3,4-dichlorobenzoyl chloride,3,5-dimethoxybenzoyl chloride, 3,4-dimethoxybenzoyl chloride,3,5-dinitrobenzoyl chloride, 2-fluorobenzoyl chloride, 3-fluorobenzoylchloride, 4-fluorobenzoyl chloride, 3-nitrobenzoyl chloride,4-nitrobenzoyl chloride, 2-methoxybenzoyl chloride, 3-methylbenzoylchloride, 4-methylbenzoyl chloride, 2-iodobenzyl chloride, 4-iodobenzoylchloride and 4-trifluoromethylbenzoyl chloride.

The compounds of Formula I hereinabove are essentially colorless in thedepicted form. When contacted with an electric current from an appliedvoltage stylus of the type ordinarily employed in electrochromicrecording systems, the compounds of Formula I develop green,green-black, black and blue-black-colored images. These developed imagesare very insensitive to light, that is, once the color is developed, itremains unchanged when subjected to light exposure. The developed imagesalso possess excellent xerographic reproducibility.

The compounds of this invention may be incorporated in any of thecommercially-accepted systems known in the electrochromic recording art.Typical techniques for the application of the color formers to paper arewell known and are described in numerous patents, for example, U.S. Pat.Nos. Re. 29,427; 3,726,769; 3,864,684; 3,871,972; 3,951,757; 4,017,366;and 4,133,933. The usual paper coatings consist of the color-formingcomponent, an organic metal salt, a binder and some type of conductor,either an inorganic salt or a conductive polymer. This mixture is milledtogether optionally in the presence of a non-ionic surface active agentuntil the desired particle size is obtained and then the mixture iscoated on paper and dried. Optionally, the color-forming substance canbe milled in the presence of a binder and the remaining componentsmilled also in the presence of a binder and the two mixtures combinedtogether prior to coating on paper. Normally the surface of the coatedpaper is wet with a conductive solution containing an inorganic alkalinemetal or alkaline earth metal salt, for example, potassium chloride,calcium chloride, sodium chloride, sodium bromide, potassium bromide,potassium nitrate or sodium sulfate immediately prior to the printingwith the applied voltage stylus. For a quick qualitative test, it hasbeen determined that the color-forming component can be dissolved in asuitable volatile organic solvent, coated on paper and the coated paperdried to obtain a paper sheet coated with the color-forming component.This coated sheet can then be wet with a conductive salt solution and animage traced with an applied voltage stylus to develop the coloredimage.

The compounds of Formula I can be used alone as color-forming componentsin electrochromic recording paper or can be used in admixture with oneor more other color-forming compounds from the classes consisting ofphthalides, for example, Crystal Violet Lactone; fluorans, for example,3-diethylamino-5,7-dimethylfluoran; redox indicators, for example,phenothiazines such as benzoyl leuco methylene blue and various othertypes of color-forming components currently employed incommercially-accepted electrochromic recording systems.

The best mode contemplated by the inventors of carrying out thisinvention will now be described so as to enable any person skilled inthe art to which it pertains to make and use the same.

In accordance with the aforementioned process aspects of this invention,the compounds of Formula I are obtained by reacting one molecularproportion of a leuco compound of Formula V with at least two molecularproportions of an acylating agent of Formula VI. When using an anhydrideas the acylating agent, the reaction is conveniently carried out in anexcess of the acylating agent which is utilized as both the reactionmedium and as the reactant. Optionally a small amount of an organicbase, for example, pyridine may be used as a catalyst. The reaction isconveniently carried out at a temperature in the range of 90° C. toreflux of the mixture for periods of approximately thirty minutes toapproximately four hours. The compounds of Formula I thus obtained areisolated by pouring the reaction mixture into ice water and extractingthe desired products into a suitable water immiscible organic liquid,for example, toluene. The organic liquid layer containing the product issubsequently washed with water to remove inorganic salts andwater-soluble organics and then treated with decolorizing charcoal, ifdesired. The resulting organic liquid solution of the product is thenconcentrated by conventional means such as evaporation or distillation.

Alternatively, the compounds of Formula I can be obtained also byreacting approximately one molecular proportion of a leuco compound ofFormula V with about two molecular proportions of an acyl halide ofFormula VI (Z=halo). A solution of the leuco compound dissolved in anorganic liquid is cooled to a temperature in the range of 60° to 80° C.and disodium phosphate and acyl halide, dissolved in the same organicliquid, is added. The reaction is conveniently carried out at the refluxtemperature of the mixture for periods of approximately fifteen minutesto approximately nineteen hours. Water and additional disodium phosphateare added to the reaction mixture and the resulting mixture is heated atreflux temperature for a period of approximately thirty minutes toapproximately one hour. The organic liquid solution containing thedesired product is separated from the water layer, washed with water andconcentrated by conventional means such as evaporation or distillation.The isolated product can be purified by conventional means such asrecrystallization or reslurrying with a suitable organic liquid and thencollected by filtration. Purification can also be effected by columnchromatography. The material to be purified is dissolved in a suitableorganic liquid and the solution is passed through a chromatographycolumn which has been packed with a suitable substrate, for example,silica gel, cellulose, alumina and the like. Numerous fractions arecollected and analyzed to determine fraction(s) containing the desiredproduct. The fraction(s) which contain the desired product are thencombined (if more than one) and concentrated to obtain the product. Theleuco compound of Formula V is conveniently prepared by reducing thecorresponding phenothiazinium or phenoxazinium halide dyestuff ofFormula IV with a reducing agent, for example, zinc dust. This reactionis conveniently carried out in an excess of the alkanoic anhydrideacylating agent thus resulting in no need for an inert organic liquidreaction medium. Alternatively, the leuco compound of Formula V isconveniently prepared by reducing the corresponding phenolthiaziniumhalide or phenoxazinium halide of Formula IV with a reducing agent, forexample, an alkaline hydrosulfite. The reaction in which the leucocompound is prepared is conveniently carried out in a mixture of waterand a suitable water immiscible organic liquid, for example, toluene orxylene in an inert atmosphere, for example, nitrogen. The reaction iscarried out in the presence of an alkaline substance, for example,sodium carbonate or disodium phosphate using, as the reducing agent, analkali hydrosulfite, for example, sodium hydrosulfite. The reaction isconveniently carried out at ambient temperature for a period ofapproximately fifteen minutes to approximately two hours. The organicliquid solution which contains the leuco compound is separated from thewater layer. Additional alkali hydrosulfite is added to the organicliquid solution and the resulting mixture is azeotroped to remove theremaining trace of water. The resulting solution can be used directly inthe acylating step of the process.

The molecular structures of the compounds were assigned on the basis ofthe modes of synthesis and a study of their infrared, nuclear magneticresonance and mass spectra.

The following examples will further illustrate the invention without,however, limiting it thereto.

EXAMPLE 1

A mixture of 10.0 g of Azure B (Aldrich)7-(dimethylamino)-3-(methylamino)phenothiazin-5-ium chloride, 75.0 ml of90 percent formic acid, 5.0 g of zinc dust and 5.0 ml of pyridine wasmaintained at approximately 90° C. for approximately three hours. Thereaction mixture was cooled to room temperature and filtered, saving thefiltrate. The filter cake was washed twice, each time with 50.0 ml ofacetone, and the washes combined with the filtrate. The combinedfiltrate and washes was poured into ice water with stirring. Theresulting solution was extracted with toluene. The toluene solution wasseparated, treated with decolorizing carbon, filtered and the resultingsolution was evaporated under reduced pressure to obtain a gummyresidue. The gummy residue was titurated with a 1:1 (V:V) mixture ofisopropyl alcohol and hexane. The solid which formed was collected byfiltration and dried to obtain 0.14 g of7-(dimethylamino)-3-(N-formyl-N-methylamino)-10-formylphenothiazine(Formula II: R=R¹ =R⁵ =H; R² =R³ =R⁴ =CH₃), an off-white-colored powderwhich melted at 139° to 143° C. A significant infrared maximum appearedat 1685 cm⁻¹ (C═O;s). A paper treated with an ink formulation of theproduct produced a black-colored image when traced with an appliedvoltage stylus.

EXAMPLE 2

A mixture of 9.0 g of7-(dimethylamino)-3-methylamino-2-methyl-phenothiazin-5-ium chloride,150.0 ml of acetic anhydride and 10.0 g of zinc dust was maintained atreflux temperature for approximately four hours. After the reactionmixture was cooled to ambient temperature, it was poured into ice waterwith stirring and toluene was added. After stirring for approximatelyone-half hour, the toluene layer was separated and washed twice, oncewith tap water and once with saturated aqueous sodium chloride solution.The toluene was then removed at reduced pressure. The residue whichremained was dissolved in ethyl acetate and separated into variouscomponents by subjecting the solution to column chromatography usingsilica gel as the substrate. The fourth and fifth fractions werecombined and the ethyl acetate evaporated to obtain 3.79 g of7-(dimethylamino)-3-(N-acetyl-N-methylamino)-2-methyl-10-acetylphenothiazine(Formula II: R=2--CH₃ ; R¹ =R² =R³ =R⁴ =CH₃ ; R⁵ =H), a white-coloredsolid which melted over the range of 148° to 161° C. A significantinfrared maximum appeared at 1665 cm⁻¹ (C═O;s). A significant maximaappeared in the mass spectrum at 369 (M⁺) and 326 (M⁺ --CH₃ CO). Papertreated with an ink formulation of the product produced a black-coloredimage when traced with an applied voltage stylus.

EXAMPLE 3

The reaction vessel was purged of residual air with nitrogen and, whilemaintaining a nitrogen atmosphere, there was placed in the vessel, 10.0g of Azure B (Aldrich)7-(dimethylamino)-3-(methylamino)-phenothiazin-5-ium chloride, 500.0 mlof water and 500.0 ml of toluene. With stirring, there was added to theresulting mixture, 10.0 g of sodium carbonate and 15.0 g of sodiumhydrosulfite. The resultant mixture was stirred for approximatelyfifteen minutes at ambient temperature and the water layer was separatedand discarded. To the toluene layer, 10.0 g of sodium hydrosulfite wasadded and the resulting mixture was heated at reflux temperature untilall of the water was azeotroped from it. After the mixture dried, it wascooled to approximately 70° C. and 15.0 g of disodium phosphate wasadded. To this mixture, there was added a solution of 20.0 ml of4-methylbenzoyl chloride dissolved in 30.0 ml of toluene. The reactionmixture was heated at reflux temperature for approximately two andone-half hours. After cooling the resulting mixture to ambienttemperature, 500.0 ml of water and 15.0 g of disodium phosphate wasadded. This mixture was then refluxed for approximately one-half hourand then cooled to room temperature. The toluene layer was separated andsaved and the water layer discarded. The toluene layer was washed twice,each time with 400.0 ml of water, once with 400.0 ml of aqueoussaturated sodium carbonate solution, then with 400.0 ml of water andfinally with 400.0 ml of aqueous saturated sodium chloride solution. Allof the aqueous washes were discarded. The toluene layer was thenevaporated to dryness under reduced pressure. The residue was reslurriedin a mixture of 200.0 ml of isopropyl alcohol, 100.0 ml of water and20.0 g of disodium phosphate at approximately 80° C. for approximatelyten minutes. After cooling, the solid was collected by filtration anddried to obtain 8.24 g of7-(dimethylamino)-3-[N-(4-methylphenylcarbonyl)-N-methylamino]-10-(4-methylphenylcarbonyl)-phenotriazine(Formula II:R=R⁵ =H; R¹ =4--CH₃ C₆ H₄ ; R² =R³ =R⁴ =CH₃), a white powderwhich melted at 220° to 224° C. Significant infrared maxima wereobserved at 1670 cm⁻¹ (C═O;s) and 1660 cm⁻¹ (C═O;s). The nuclearmagnetic resonance spectrum was in accord with the assigned structure.Paper treated with an ink formulation of the product produced ablack-colored image when traced with an applied voltage stylus.

Proceeding in a manner similar to that described in Example 2 above, theappropriate phenothiazinium or phenoxazinium halide described in thesecond column of Part 1 of Table A hereinbelow was reduced in thereaction medium indicated in the third column of Part 1 with thereducing agent listed in column 4 and subsequently acylated with theacylating agent given in the fifth column of Part 1 at the temperatureindicated in column 6 for the period of time specified in the seventhcolumn of Part 1. The product obtained is given in the second column ofPart 2 of Table A having the structural formula referred to in the thirdcolumn of Part 2 with its physical appearance described in the fourthcolumn of Part 2. Its melting point is shown in the fifth column of Part2, significant infrared is shown in the sixth column of Part 2, andnuclear magnetic resonance spectral analysis is shown in the seventhcolumn of Part 2. The color produced when a paper sheet treated with anink formulation containing the product was traced with an appliedvoltage stylus is described in the eighth column of Part 2.

                                      TABLE A                                     __________________________________________________________________________    Part 1                                                                        Example                                                   Reaction            No.      Starting Material                                                                         Reaction Medium                                                                          Reducing Agent                                                                        Acylating Agent                                                                          Temperature                                                                          Time                __________________________________________________________________________     4   8.0 g                                                                             7-(Dimethylamino)-3-                                                                      100.0 ml                                                                           Acetic                                                                              10.0 g                                                                            Zinc                                                                              100.0                                                                            ml                                                                              Acetic                                                                              Reflux 0.5 Hour                     (methylamino)phenothi-                                                                         anhydride dust     anhydride                                 azin-5-ium bromide                                                                        10.0 ml                                                                            Pyridine                                             5   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water 10.0 g                                                                            Sodium                                                                            27.6                                                                             ml                                                                              2-Naph-                                                                             Reflux   2 Hours                    (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene   hydro-   thoic acid                                azin-5-ium chloride        sulfite  chloride                          6   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water 10.0 g                                                                            Sodium                                                                            20.0                                                                             ml                                                                              Benzoyl                                                                             Reflux   2 Hours                    (methylamino)-2-bromo-                                                                    500.0 ml                                                                           Toluene   hydro-   chloride                                  phenothiazin-5-ium         sulfite                                            chloride                                                              7   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water 10.0 g                                                                            Sodium                                                                            20.0                                                                             g Diphenyl-                                                                           Reflux 2.5 Hours                    (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene   hydro-   acetyl                                    azin-5-ium chloride        sulfite  chloride                          8   9.0 g                                                                             7-(Dibutylamino)-3-                                                                       75.0 ml                                                                            Acetic                                                                              5.0 g                                                                             Zinc                                                                              75.0                                                                             ml                                                                              Acetic                                                                              Reflux 1.5 Hours                    (methylamino)phenothi-                                                                         anhydride dust     anhydride                                 azin-5-ium chloride                                                                       5.0 ml                                                                             Pyridine                                             9   6.0 g                                                                             7-(Dimethylamino)-3-                                                                      80.0 ml                                                                            Acetic                                                                              4.0 g                                                                             Zinc                                                                              80.0                                                                             ml                                                                              Acetic                                                                              Reflux 0.5 Hour                     (ethylamino)phenothi-                                                                          anhydride dust     anhydride                                 azin-5-ium chloride                                                           zinc chloride double                                                          salt                                                                 10   8.0 g                                                                             7-(Diethylamino)-3-                                                                       80.0 ml                                                                            Acetic                                                                              4.0 g                                                                             Zinc                                                                              80.0                                                                             ml                                                                              Acetic                                                                              Reflux 0.5 Hour                     (methylamino)phenothi-                                                                         anhydride dust     anhydride                                 azin-5-ium chloride                                                           zinc chloride double                                                          salt                                                                 11   8.0 g                                                                             7-(Diethylamino)-3-                                                                       400.0 ml                                                                           Water 25.0 g                                                                            Sodium                                                                            30.0                                                                             ml                                                                              Benzoyl                                                                             Reflux  18 Hours                    (methylamino)phenothi-                                                                    400.0 ml                                                                           Toluene   hydro-   chloride                                  azin-5-ium chloride        sulfite                                            zinc chloride double                                                          salt                                                                 12   8.0 g                                                                             7-(Dimethylamino)-3-                                                                      400.0 ml                                                                           Water 25.0 g                                                                            Sodium                                                                            30.0                                                                             ml                                                                              Benzoyl                                                                             Reflux  19 Hours                    (methylamino)phenothi-                                                                    400.0 ml                                                                           Toluene   hydro-   chloride                                  azin-5-ium chloride        sulfite                                            zinc chloride double                                                          salt                                                                 13   5.0 g                                                                             7-(Dimethylamino)-3-                                                                      250.0 ml                                                                           Water 15.0 g                                                                            Sodium                                                                            10.0                                                                             g Methoxy-                                                                            Reflux 2.5 Hours                    (methylamino)phenothi-                                                                    250.0 ml                                                                           Toluene   hydro-   acetyl                                    azin-5-ium chloride        sulfite  chloride                         14   6.43 g                                                                            7-(N--Benzyl-N--ethyl-                                                                    65.0 ml                                                                            Acetic                                                                              6.5 g                                                                             Zinc                                                                              65.0                                                                             ml                                                                              Acetic                                                                              Reflux 0.5 Hour                     amino)-3-(methylamino)-                                                                        anhydride dust     anhydride                                 phenothiazin-5-ium                                                            chloride                                                             15   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water 10.0 g                                                                            Sodium                                                                            25.0                                                                             g 2,6-Di-                                                                             Reflux 2.5 Hours                    (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene   hydro-   fluoro-                                   azin-5-ium chloride        sulfite  benzoyl                                                                       chloride                         __________________________________________________________________________    Part 2                                                                                                          Physical                Produced            Example                           Appear-                                                                            Melting                                                                            Significant   Image               No.      Product Name Product Formula                                                                           ance Point                                                                              Infrared                                                                            NMR     Color               __________________________________________________________________________     4   1.85 g                                                                            7-(Dimethylamino)-3-(N--                                                                   II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 White                                                                              147- 1690 cm.sup.-1                                                                      Consistent                                                                            Black                        acetyl-N--methylamino)-                                                                    R.sup.2 ═ R.sup.3 ═ R.sup.4 ═                                                 Powder.3                                                                           155° C.                                                                     (C═ O;s)                               10-acetylphenothiazine                                                5   0.16 g                                                                            7-(Dimethylamino)-3-(N--                                                                   II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Tan  117- 1650 cm.sup.-1                                                                              Black                        2-naphthylcarbonyl-N--                                                                     2-C.sub.10 H.sub.7 ; R.sup.2 ═ R.sup.3 ═                                          Powder                                                                             122° C.                                                                     (C═ O;s)                               methylamino)-10-(2-                                                                        R.sup.4 ═ CH.sub.3                                           naphthylcarbonylpheno-                                                        thiazine                                                              6   1.39 g                                                                            7-(Dimethylamino)-3-(N--                                                                   II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Pale 79-  1655 cm.sup.-1                                                                              Blue-                        benzoyl-N--methylamino)-                                                                   C.sub.6 H.sub.5 ; R.sup.2 ═ R.sup.3 ═                                 R.sup.4 ═                                                                             Green-                                                                             84° C.                                                                      (C═ O;s)  black                        10-benzoylphenothiazine                                                                    CH.sub.3    yellow                                                                        Powder                                       7   1.3 g                                                                             7-(Dimethylamino)-3-(N--                                                                   II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Tan  78-  1660 cm.sup.-1                                                                      Consistent                                                                            Black                        diphenylacetyl-N--methyl-                                                                  4-C.sub.4 H.sub.5 C.sub.6 H.sub.4 ; R.sup.2 ═                                         Powder                                                                             86° C.                                                                      (C═ O;s)                               amino)-10-diphenylacetyl                                                                   R.sup.3 ═ R.sup.4 ═ CH.sub.3                             phenothiazine                                                         8   0.86 g                                                                            7-(Dibutylamino)-3-(N--                                                                    II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Brown                                                                              --   1670 cm.sup.-1                                                                              Black                        acetyl-N--methylamino)-                                                                    R.sup.2 ═ CH.sub.3 ; R.sup.3 ═ R.sup.4                                ═       Gum       (C═ O;s)                               10-acetylphenothiazine                                                                     C.sub.4 H.sub.9                                          9   0.52 g                                                                            7-(Dimethylamino)-3-(N--                                                                   II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Yellow                                                                             107- 1675 cm.sup.-1                                                                              Green-                       acetyl-N--ethylamino)-                                                                     R.sup.3 ═ R.sup.4 ═ CH.sub.3 ; R.sup.2                                ═       Powder                                                                             110° C.                                                                     (C═ O;s)  black                        10-acetylphenothiazine                                                                     C.sub.2 H.sub.5                                         10   1.0 g                                                                             7-(Diethylamino)-3-(N--                                                                    II: R═ R.sup.5 ═ H; R.sup. 1                                                      Tand.                                                                              92.5-                                                                              1665 cm.sup.-1                                                                      Consistent                                                                            Green-                       acetyl-N--methylamino)-                                                                    R.sup.2 ═ CH.sub.3 ; R.sup.3 ═ R.sup.4                                ═       Powder                                                                             97° C.                                                                      (C═ O;s)  black                        10-acetylphenothiazine                                                                     C.sub.2 H.sub.5                                         11   1.04 g                                                                            7-(Diethylamino)-3-(N--                                                                    II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Brown                                                                              --   1660 cm.sup.-1                                                                              Black                        benzoyl-N--methylamino)-                                                                   C.sub.6 H.sub.5 ; R.sup.2 ═ CH.sub.3 ;                                                Gum       (C═ O;s)                               10-benzoylphenothiazine                                                                    R.sup.3 ═ R.sup.4 ═ C.sub.2 H.sub.5             12   1.0 g                                                                             7-(Dimethylamino)-3-(N--                                                                   II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Brown                                                                              100- 1650 cm.sup.-1                                                                              Black                        benzoyl-N--ethylamino)-                                                                    C.sub.6 H.sub.5 ; R.sup.2 ═ C.sub.2 H.sub.5                                           Powder                                                                             130° C.                                                                     (C═ O;s)                               10-benzoylphenothiazine                                                                    R.sup.3 ═ R.sup.4 ═ CH.sub.3                    13   3.54 g                                                                            7-(Dimethylamino)-3-(N--                                                                   II: R═ R.sup. 5 ═ H; R.sup.1 ═                                                Brown                                                                              --   1667 cm.sup.-1                                                                      Consistent                                                                            Black                        methoxyacetyl-N--methyl-                                                                   CH.sub.3 OCH.sub.2 ; R.sup.2 ═ R.sup.3 ═                                          Gum       (C═ O;s)                               amino)-10-methoxyacetyl-                                                                   R.sup.4 ═ CH.sub.3                                           phenothiazine                                                        14   0.52 g                                                                            7-(N--Benzyl-N--ethyl-                                                                     II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Brown                                                                              65-  1670 cm.sup.-1                                                                              Black                        amino)-3-(N--acetyl-N--                                                                    R.sup.2 ═ CH.sub.3 ; R.sup.3 ═                                                    Powder                                                                             69° C.                                                                      (C═  O;s)                              methylamino)-10-acet-                                                                      C.sub.6 H.sub.5 CH.sub.2 ; R.sup.4 ═                         ylphenothiazine                                                                            C.sub.2 H.sub.5                                         15   3.60 g                                                                            7-(Dimethylamino)-3-                                                                       II: R═ R.sup.5 ═ H; R.sup.1 ═                                                 Pale 106- 1670 cm.sup.-1                                                                              Black                        [N--(2,6-difluorobenz-                                                                     2,6-F.sub.2 C.sub.6 H.sub.3 ; R.sup.2 ═                                               Brown                                                                              112° C.                                                                     (C═ O;s)                               oyl)-N--methylamino]-10-                                                                   R.sup.3 ═ R.sup.4 ═ CH.sub.3                                                      Powder                                               (2,6-difluorobenzoyl)-                                                        phenothiazine                                                        __________________________________________________________________________

Proceeding in a manner similar to that described in Example 3 above, theappropriate phenothiazinium halide described in the second column ofPart 1 of Table B hereinbelow was reduced in the reaction mediumindicated in the third column of Part 1 with the reducing agent listedin column 4 and subsequently acylated with the acylating agent given inthe fifth column of Part 1 at the temperature indicated in column 6 forthe period of time specified in the seventh column of Part 1. Theproduct obtained is given in the second column of Part 2 of Table Bhaving the structural formula referred to in the third column of Part 2with its physical appearance described in the fourth column of Part 2.Its melting point is shown in the fifth column of Part 2, significantinfrared in the sixth column of Part 2, and nuclear magnetic resonancespectral analysis is shown in the seventh column of Part 2. The colorproduced when a paper sheet treated with an ink formulation containingthe product was traced with an applied voltage stylus is described inthe eighth column of Part 2.

                                      TABLE B                                     __________________________________________________________________________    Part 1                                                                        Example                                                  Reaction             No.      Starting Material                                                                         Reaction Medium                                                                         Reducing Agent                                                                        Acylating Agent                                                                          Temperature                                                                          Time                 __________________________________________________________________________    16   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            20.0                                                                             ml                                                                              4-Methyl-                                                                           Reflux 2.5 Hours                     (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   benzoyl                                    azin-5-ium chloride       sulfite  chloride                          17   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            20.0                                                                             ml                                                                              3-Nitro-                                                                            Reflux 2 Hours                       (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   benzoyl                                    azin-5-ium chloride       sulfite  chloride                          18   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            20.0                                                                             ml                                                                              Phenoxy-                                                                            Reflux 2 Hours                       (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   acetyl                                     azin-5-ium chloride       sulfite  chloride                          19   6.0 g                                                                             7-(Dimethylamino)-3-                                                                      300.0 ml                                                                           Water                                                                              12.0 g                                                                            Sodium                                                                            10.0                                                                             g 4-Bromo-                                                                            Reflux 19 Hours                      (methylamino)phenothi-                                                                    300.0 ml                                                                           Toluene  hydro-   benzoyl                                    azin-5-ium chloride       sulfite  chloride                          20   6.0 g                                                                             7-(Dimethylamino)-3-                                                                      300.0 ml                                                                           Water                                                                              12.0 g                                                                            Sodium                                                                            10.0                                                                             g 4-Phenyl-                                                                           Reflux 19 Hours                      (methylamino)phenothi-                                                                    300.0 ml                                                                           Toluene  hydro-   benzoyl                                    azin-5-ium chloride       sulfite  chloride                          21   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            25.0                                                                             g Cyclohex-                                                                           Reflux 2 Hours                       (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   ane carbox-                                azin-5-ium chloride       sulfite  ylic acid                                                                     chloride                          22   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            20.0                                                                             ml                                                                              2-Methyl-                                                                           Reflux 2 Hours                       (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   benzoyl                                    azin-5-ium chloride       sulfite  chloride                          23   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            20.0                                                                             ml                                                                              2-Chloro-                                                                           Reflux 2 Hours                       (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   benzoyl                                    azin-5-ium chloride       sulfite  chloride                          24   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            25.0                                                                             g 3,4,5-Tri-                                                                          Reflux 2 Hours                       (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   methoxy-                                   azin-5-ium chloride       sulfite  benzoyl                                                                       chloride                          25   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            20.0                                                                             ml                                                                              3-Carbo-                                                                            Reflux 2 Hours                       (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   methoxy-                                   azin-5-ium chloride       sulfite  propanyl                                                                      chloride                          26   5.0 g                                                                             7-(Dimethylamino)-3-                                                                      250.0 ml                                                                           Water                                                                              5.0 g                                                                             Sodium                                                                            5.0                                                                              g 4-Cyano-                                                                            Reflux 2 Hours                       (methylamino)phenothi-                                                                    250.0 ml                                                                           Toluene  hydro-   benzoyl                                    azin-5-ium chloride       sulfite  chloride                          27   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              10.0 g                                                                            Sodium                                                                            25.0                                                                             ml                                                                              Decanoyl                                                                            Reflux 2 Hours                       (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   chloride                                   azin-5-ium chloride       sulfite                                    28   13.0 g                                                                            7-(Dimethylamino)-3-                                                                      400.0 ml                                                                           Water                                                                              25.0 g                                                                            Sodium                                                                            30.0                                                                             ml                                                                              Benzoyl                                                                             Reflux 4 Hours                       (methylamino)phenothi-                                                                    400.0 ml                                                                           Toluene  hydro-   chloride                                   azin-5-ium chloride       sulfite                                    29   30.0 g                                                                            7-(Dimethylamino)-3-                                                                      1500.0 ml                                                                          Water                                                                              30.0 g                                                                            Sodium                                                                            50.0                                                                             ml                                                                              4-Anisoyl                                                                           Reflux 2 Hours                       (methylamino)phenothi-                                                                    1500.0 ml                                                                          Toluene  hydro-   chloride                                   azin-5-ium chloride       sulfite                                    30   5.0 g                                                                             7-(Dimethylamino)-3-                                                                      250.0 ml                                                                           Water                                                                              7.5 g                                                                             Sodium                                                                            15.0                                                                             g 3,4-Di-                                                                             Reflux 2 Hours                       (methylamino)phenothi-                                                                    300.0 ml                                                                           Toluene  hydro-   chloro-                                    azin-5-ium chloride       sulfite  benzoyl                                                                       chloride                          31   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              15.0 g                                                                            Sodium                                                                            20.0                                                                             g 2,4,6-Tri-                                                                          Reflux 2.5 Hours                     (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   methyl-                                    azin-5-ium chloride       sulfite  benzoyl                                                                       chloride                          32   10.0 g                                                                            7-(Dimethylamino)-3-                                                                      500.0 ml                                                                           Water                                                                              15.0 g                                                                            Sodium                                                                            20.0                                                                             g 2-Tri-                                                                              Reflux 2.5 Hours                     (methylamino)phenothi-                                                                    500.0 ml                                                                           Toluene  hydro-   fluorometh-                                azin-5-ium chloride       sulfite  ylbenzoyl                                                                     chloride                          __________________________________________________________________________    Part 2                                                                                                          Physical                Produced            Example                           Appear-                                                                            Melting                                                                            Significant   Image               No.      Product Name Product Formula                                                                           ance Point                                                                              Infrared                                                                            NMR     Color               __________________________________________________________________________    16   8.24 g                                                                            7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            White                                                                              220- 1670 cm.sup.-1                                                                      Consistent                                                                            Black                        (4-methylphenylcarbon-                                                                     4-CH.sub.3 C.sub.6 H.sub.4 ; R.sup.2                                                      Powder                                                                             224° C.                                                                     (C = O;s)                                  yl)-N--methylamino]-10-                                                                    R.sup.3 = R.sup.4 = CH.sub.3                                                                        1660 cm.sup.-1                             (4-methylphenylcarbon-             (C = O;s)                                  yl)phenothiazine                                                     17   9.7 g                                                                             7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale 85-  1665 cm.sup.-1                                                                              Black                        (3-nitrophenylcarbon-                                                                      3-NO.sub.2 C.sub.6 H.sub.4 ; R.sup.2                                                      Brown                                                                              100° C.                                                                     (C = O;s)                                  yl)-N--methylamino]-10-                                                                    R.sup.3 = R.sup.4 = CH.sub.3                                                              Powder                                                                             (dec.)                                                                             1650 cm.sup.-1                             (3-nitrophenylcarbon-              (C = O;s)                                  yl)phenothiazine                                                     18   5.5 g                                                                             7-(Dimethylamino)-3-(N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            White                                                                              110° C.                                                                     1690 cm.sup.-1                                                                      Consistent                                                                            Gray                         phenoxyacetyl-N--methyl                                                                    C.sub.6 H.sub.5 OCH.sub.2 ; R.sup.2                                                       Powder                                                                             (dec.)                                                                             (C = O;s)                                  amino)-10-phenoxyacet-                                                                     R.sup.3 = R.sup.4 = CH.sub.3                                                                        1676 cm.sup.-1                             ylphenothiazine                    (C = O;s)                         19   8.3 g                                                                             7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale 178- 1650 cm.sup.-1                                                                              Black                        (4-bromophenylcarbonyl)-                                                                   4-BrC.sub.6 H.sub.4 ; R.sup.2 =                                                           Green                                                                              180° C.                                                                     (C = O;s)                                  N--methylamino]-10-(4-                                                                     R.sup.3 = R.sup.4 = CH.sub.3                                                              Powder    1665 cm.sup.-1                             bromophenylcarbonyl)-              (C = O;s)                                  phenothiazine                                                        20   3.1 g                                                                             7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale 165- 1662 cm.sup.-1                                                                      Consistent                                                                            Black                        (4-phenylphenylcarbon-                                                                     4-C.sub.6 H.sub.5 C.sub.6 H.sub.5 ; R.sup.2                                               Green                                                                              170° C.                                                                     (C = O;s)                                  yl)-N--methylamino]-10-                                                                    R.sup.3 = R.sup.4 = CH.sub.3                                                              Powder                                                                             (dec.)                                                                             1645 cm.sup.-1                             (4-phenylphenylcarbon-             (C = O;s)                                  yl)phenothiazine                                                     21   7.7 g                                                                             7-(Dimethylamino)-3-(N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale --   1662 cm.sup.-1                                                                              Black                        cyclohexylcarbonyl-N--                                                                     C.sub.6 H.sub.11 ; R.sup.2 = R.sup.3 = R.sup.4                                            Yellow    (C = O;s)                                  methylamino)-10-cyclo-                                                                     CH.sub.3    Gum                                                  hexylcarbonylphenothi-                                                        azine                                                                22   12.1 g                                                                            7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            White                                                                              211- 1667 cm.sup.-1                                                                              Black                        (2-methylphenylcarbon-                                                                     2-CH.sub.3 C.sub.6 H.sub.4 ; R.sup.2                                                      Powder                                                                             214° C.                                                                     (C = O;s)                                  yl)-N--methylamino]-10-                                                                    R.sup.3 = R.sup.4 = CH.sub.3                                                                        1650 cm.sup.-1                             (2-methylphenylcarbon-             (C = O;s)                                  yl)phenothiazine                                                     23   12.1 g                                                                            7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            White                                                                              236- 1670 cm.sup.-1                                                                              Black                        (2-chlorophenylcarbon-                                                                     2-ClC.sub.6 H.sub.9 ; R.sup.2 =                                                           Powder                                                                             243° C.                                                                     (C = O;s)                                  yl)-N--methylamino]-10-                                                                    R.sup.3 = R.sup.4 = CH.sub.3                                                                        1652 cm.sup.-1                             (2-chlorophenylcarbon-             (C = O;s)                                  yl)phenothiazine                                                     24   14.2 g                                                                            7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale Tarry                                                                              1663 cm.sup.-1                                                                              Black                        (3,4,5-trimethoxyphen-                                                                     3,4,5-(CH.sub.3 O).sub.3 C.sub.6 H.sub.2 ;                                                Brown     (C = O;s)                                  ylcarbonyl)-N--methyl-                                                                     R.sup.2 = R.sup.3 = R.sup.4 = CH.sub.3                                                    Powder    1650 cm.sup.-1                             amino]-10-(3,4,5-tri-              (C = O;s)                                  methylphenylcarbonyl)-                                                        phenothiazine                                                        25   14.2 g                                                                            7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 = 3-                                                         Pale --   1740 cm.sup.-1                                                                              Black                        (3-carbomethoxypropyl-                                                                     CH.sub.3 OCOC.sub.3 H.sub.6 ; R.sup.2                                                     Yellow    (C = O;s)                                  carbonyl)-N--methylamino]-                                                                 R.sup.3 = R.sup.4 = CH.sub.3                                                              Gum       1665 cm.sup.-1                             10-(3-carbomethoxypropyl-          (C = O;s)                                  carbonyl)phenothiazine                                               26   6.0 g                                                                             7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale 139- 1648 cm.sup.-1                                                                              Black                        (4-cyanophenylcarbon-                                                                      4-CNC.sub.6 H.sub.4 ; R.sup.2 = R.sup.3                                                   Yellow                                                                             155° C.                                                                     (C = O;s)                                  yl)-N--methylamino]-10-                                                                    R.sup.4 = CH.sub.3                                                                             (dec.)                                                                             1655 cm.sup.-1                             (4-cyanophenylcarbon-              (C = O;m)                                  yl)phenothiazine                                                     27   2.4 g                                                                             7-(Dimethylamino)-3-(N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale --   1670 cm.sup.-1                                                                              Black                        decanylcarbonyl-N--meth-                                                                   C.sub.10 H.sub.21 ; R.sup.2 = R.sup.3 =  R.sup.4                                          Green     (C = O;s) -   ylamino)-10-deca                                                              nyl- CH.sub.3 Ta                                                              r                            carbonylphenothiazine                                                28   1.84 g                                                                            7-(Dimethylamino)-3-(N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            White                                                                              235° C.                                                                     1670 cm.sup.-1                                                                      Consistent                                                                            Black                        phenylcarbonyl-N--meth-                                                                    C.sub.6 H.sub.5 ; R.sup.2 = R.sup.3 = R.sup.4                                             Powder    (C = O;s)                                  ylamino)-10-phenyl-                                                                        CH.sub.3              1655 cm.sup.-1                             carbonylphenothiazine              (C = O;s)                         29   26.9 g                                                                            7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            White                                                                              228.5-     (Mass                                                                                 Blackra                      (4-methoxyphenylcarbon-                                                                    4-CH.sub.3 OC.sub.6 H.sub.4 ; R.sup.2                                                     Powder                                                                             230° C.                                                                           and Elemental                        yl)-N--methylamino]-10-                                                                    R.sup.3 = R.sup.4 = CH.sub.3                                                                              Analysis Both                        (4-methoxyphenylcarbon-                  Consistent)                          yl)phenothiazine                                                     30   4.5 g                                                                             7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 =  H; R.sup.1 =                                                           Yellow                                                                             223.5-                                                                             1670 cm.sup.-1                                                                      Consistent                                                                            Black                        3,4-dichlorophenylcarbon-                                                                  3,4-ClC.sub.6 H.sub.3 ; R.sup.2 =                                                         Powder                                                                             225° C.                                                                     (C = O;s)                                  yl)-N--methylamino]-10-                                                                    R.sup.3 = R.sup.4 = CH.sub.3                                                                        1645 cm.sup.-1                             (3,4-dichlorophenyl-               (C = O;s)                                  carbonyl)phenothiazine                                               31   4.48 g                                                                            7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale 192- 1635 cm.sup.-1                                                                      Consistent                                                                            Black                        (2,4,6-trimethylphenyl-                                                                    2,4,6-(CH.sub.3).sub.3 C.sub.6 H.sub.2 ;                                                  Green                                                                              194° C.                                                                     (C = O;s)                                  carbonyl)-N--methylamino]-                                                                 R.sup.2 = R.sup.3 = R.sup.4 = CH.sub.3                                                    Powder                                               10-(2,4,6-trimethylphen-                                                      ylcarbonyl)phenothiazine                                             32   1.02 g                                                                            7-(Dimethylamino)-3-[N--                                                                   II: R = R.sup.5 = H; R.sup.1 =                                                            Pale 198- 1675 cm.sup.-1                                                                              Black                        (2-trifluoromethylphen-                                                                    F.sub.3 CC.sub.6 H.sub.4 ; R.sup.2 = R.sup.3 =                                            Gray 210° C.                                                                     (C = O;s)                                  ylcarbonyl)-N--methyl-                                                                     R.sup.4 = CH.sub.3    1663 cm.sup.-1                             amino]-10-(2-trifluoro-            (C = O;s)                                  methylphenylcarbonyl)-                                                        phenothiazine                                                        __________________________________________________________________________

Proceeding in a manner similar to that described in Example 3 above, theappropriate phenothiazinium halide described in the second column ofPart 1 of Table C hereinbelow was reduced in the reaction mediumindicated in the third column of Part 1 with the reducing agent listedin column 4 and subsequently acylated with the acylating agent given inthe fifth column of Part 1 at the temperature indicated in column 6 forthe period of time specified in the seventh column of Part 1. Theproduct obtained is given in the second column of Part 2 of Table Chaving the structural formula referred to in the third column of Part 2with its physical appearance described in the fourth column of Part 2.Its melting point is shown in the fifth column of Part 2, significantinfrared in the sixth column of Part 2, and nuclear magnetic resonancespectral analysis is shown in the seventh column of Part 2. The colorproduced when a paper sheet treated with an ink formulation containingthe product was traced with an applied voltage stylus is described inthe eighth column of Part 2.

                                      TABLE C                                     __________________________________________________________________________    Part 1                                                                        Example                                                  Reaction             No.      Starting Material                                                                        Reaction Medium                                                                          Reducing Agent                                                                        Acylating Agent                                                                         Temperature                                                                           Time                 __________________________________________________________________________    33   10.0 g                                                                            7-(Dimethylamino)-3-                                                                     5.0                                                                              ml                                                                              Pyridine                                                                            5.0 g                                                                             Zinc                                                                              50.0                                                                             ml                                                                              Hexanoic                                                                            100-110°                                                                      2 Hours                       methylamino)pheno-                                                                       50.0                                                                             ml                                                                              Hexanoic  dust     anhydride                                  thiazin-5-ium   anhydride                                                     chloride                                                             34   10.0 g                                                                            7-(Dimethylamino)-3-                                                                     5.0                                                                              ml                                                                              Pyridine                                                                            5.0 g                                                                             Zinc                                                                              50.0                                                                             ml                                                                              Butyric                                                                             100-110°                                                                      2 Hours                       methylamino)pheno-                                                                       50.0                                                                             ml                                                                              Butyric   dust     anhydride                                  thiazin-5-ium   anhydride                                                     chloride                                                             35   10.0 g                                                                            7-(Dimethylamino)-3-                                                                     5.0                                                                              ml                                                                              Pyridine                                                                            5.0 g                                                                             Zinc                                                                              50.0                                                                             ml                                                                              Trimethyl-                                                                          100-105°                                                                      3 Hours                       methylamino)pheno-                                                                       50.0                                                                             ml                                                                              Trimethyl dust     acetic                                     thiazin-5-ium   acetic             anhydride                                  chloride        anhydride                                            36   10.0 g                                                                            7-(Dimethylamino)-3-                                                                     5.0                                                                              ml                                                                              Pyridine                                                                            5.0 g                                                                             Zinc                                                                              25.0                                                                             g Trichloro-                                                                          Reflux 3 Hours                       methylamino)pheno-                                                                       100.0                                                                            ml                                                                              Acetone   dust     acetic                                     thiazin-5-ium                                                                            25.0                                                                             g Trichloro-         anhydride                                  chloride        acetic                                                                        anhydride                                            37   10.0 g                                                                            2-Methyl-3-amino-7-                                                                      50.0                                                                             ml                                                                              Acetic                                                                              10.0 g                                                                            Zinc                                                                              50.0                                                                             ml                                                                              Acetic                                                                              85-90° C.                                                                     1 Hour                        dimethylaminopheno-                                                                           Anhydride dust     Anhydride                                  thiazin-5-ium                                                                            10.0                                                                             ml                                                                              Pyridine                                                      chloride                                                             38   15.0 g                                                                            2-Methyl-3-amino-7-                                                                      400.0                                                                            ml                                                                              Water 40.0 g                                                                            Sodium                                                                            20.0                                                                             ml                                                                              Benzoyl                                                                             60-65° C.                                                                     1 Hour                        dimethylaminopheno-                                                                      400.0                                                                            ml                                                                              Toluene   Hydro-   Chloride                                   thiazin-5-ium             sulfite                                             chloride                                                             39   10.0 g                                                                            2-Methyl-3-amino-7-                                                                      400.0                                                                            ml                                                                              Water 30.0 g                                                                            Sodium                                                                            25.0                                                                             ml                                                                              Anisoyl                                                                             Reflux 2.5 Hours                     dimethylaminopheno-                                                                      400.0                                                                            ml                                                                              Toluene   Hydro-   Chloride                                   thiazin-5-ium             sulfite                                             chloride                                                             40   10.0 g                                                                            2-Methyl-3-amino-7-                                                                      75.0                                                                             ml                                                                              Butyric                                                                             6.0 g                                                                             Zinc                                                                              75.0                                                                             ml                                                                              Butyric                                                                             70° C.                                                                        4 Hours                       dimethylaminopheno-                                                                           Anhydride Dust     Anhydride                                  thiazin-5-ium                                                                            10.0                                                                             ml                                                                              Pyridine                                                      chloride                                                             __________________________________________________________________________    Part 2                                                                                                            Physical                                                                            Melt-           Produced            Example                             Appear-                                                                            ing Significant  Image               No.      Product Name  Product Formula                                                                            ance Point                                                                             Infrared                                                                            NMR    Color               __________________________________________________________________________    33   31.57 g                                                                           7-(Dimethylamino)-3-(N--                                                                    II: R = R.sup.5 = H; R.sup.1 =                                                             Brown                                                                              --  1670 cm.sup.-1                                                                      Consistent                                                                           Black                        hexanoyl-N--methylamino)-                                                                   C.sub.6 H.sub.13 ; R.sup.2 = R.sup.3 = R.sup.4                                             Gummy    (C = O;s)                                 10-hexanoylphenothiazine                                                                    CH.sub.3     Solid                                     34   24.4 g                                                                            7-(Dimethylamino)-3-(N--                                                                    II: R = R.sup.5 = H; R.sup.1 =                                                             Orange-                                                                            --  1660 cm.sup.-1                                                                      Consistent                                                                           Black                        butyryl-N--methylamino)-                                                                    C.sub.4 H.sub.9 ; R.sup.2 = R.sup.3 = R.sup.4                                              brown    (C = O;s)                                 10-butyrylphenothiazine                                                                     CH.sub.3     Gummy                                                                         Solid                                     35   5.49 g                                                                            7-(Dimethylamino)-3-(N--                                                                    II: R = R.sup.5 = H; R.sup.1 =                                                             Dark 174-                                                                              1620 cm.sup.-1                            trimethylacetyl-N--meth-                                                                    (CH.sub.3).sub.3 C; R.sup. 2 = R.sup.3                                                     Green                                                                              180° C.                                                                    (C = O;s)                                 ylamino)-10-trimethyl-                                                                      R.sup.4 = CH.sub.3                                                                         Powder                                             acetylphenothiazine                                                  36   5.9 g                                                                             7-(Dimethylamino)-3-(N--                                                                    II: R = R.sup.5 = H; R.sup.1 =                                                             Blue 280-                                                                              1675 cm.sup.-1                            trichloroacetyl-N--meth-                                                                    Cl.sub.3 C; R.sup.2 = R.sup.3 =                                                            Powder                                                                             285° C.                                                                    (C = O;s)                                 ylamino)-10-trichloro-                                                                      R.sup.4 = CH.sub.3                                              acetylphenothiazine                                                  37   0.95 g                                                                            2-Methyl-3-acetamido-7-                                                                     II: R = 2-CH.sub.3 ; R.sup.1 =                                                             Tan  157-                                                                              1668 cm.sup.-1                                                                      Consistent                                                                           Gray                         dimethylamino-10-acetyl-                                                                    R.sup.3 = R.sup.4 = CH.sub.3 ; R.sup.2                                                     Powder                                                                             159° C.                                                                    (C = O;s)                                                                           (Mass Spec.                         phenothiazine                             Consistent)                38   1.8 g                                                                             2-Methyl-3-benzamido-7-                                                                     II: R = 2-CH.sub.3 ; R.sup.1 =                                                             Yellow                                                                             167-                                                                              1650 cm.sup.-1                                                                             Gray                         dimethylamino-10-ben-                                                                       C.sub.6 H.sub.5 ; R.sup.2 = H; R.sup.3                                                     Powder                                                                             175° C.                                                                    (C = O;s)                                 zoylphenothiazine                                                                           R.sup.4 = CH.sub.3                                     39   2.65 g                                                                            2-Methyl-3-(4-methyl-                                                                       II: R = 2-CH.sub.3 ; R.sup.1 =                                                             Pale 238-                                                                              1650 cm.sup.-1                                                                             Blue-                        phenylamido)-7-dimeth-                                                                      4-CH.sub.3 C.sub.6 H.sub.4 ; R.sup.2                                                       Yellow                                                                             242° C.                                                                    (C = O;s)    gray                         ylamino-10-(4-methyl-                                                                       R.sup.3 = R.sup.4 = CH.sub.3                                                               Powder                                             phenylcarbonyl)pheno-                                                         thiazine                                                             40   1.46 g                                                                            2-Methyl-3-butyryl-                                                                         II: R = 2-CH.sub.3 ; R.sup.1 =                                                             White                                                                              208-                                                                              1665 cm.sup.-1                                                                      Consistent                                                                           Blue-                        amido-7-dimethylamino-                                                                      C.sub.3 H.sub.7 ; R.sup.2 = H; R.sup.3                                                     Powder                                                                             210° C.                                                                    (C = O;s)    gray                         10-butyrylcarbonylpheno-                                                                    R.sup.4 = CH.sub.3                                              thiazine                                                             __________________________________________________________________________

It is contemplated that by following the procedure described in theforegoing examples, but employing the appropriate 1/2-R-3-(N-R²-amino)-7-(N-R³ -N-R⁴ -amino)phenothiazinium halide or phenoxaziniumhalide of Formula IV with a reducing agent and the appropriate acidhalide of Formula VII or alkanoic acid anhydride of Formula VI, therewill be obtained 1/2-R-3-(N-R² -N-COR¹ -amino)-7-(N-R³ -N-R⁴-amino)-10-(R¹ -CO)phenothiazine or phenoxazine of Formula I, presentedin Examples 41 to 59 in Table D hereinbelow.

                                      TABLE D                                     __________________________________________________________________________    Example No.                                                                          R   R.sup.1 R.sup.2 R.sup.3   R.sup.4   R.sup.5                        __________________________________________________________________________    41     C.sub.2 H.sub.5 O                                                                 ClCH.sub.2                                                                            CH.sub.3                                                                              C.sub.6 H.sub.5 CH.sub.2                                                                C.sub.6 H.sub.5 CH.sub.2                                                                H                              42     Cl  CH.sub.3 OCH.sub.2                                                                    C.sub.2 H.sub.5                                                                       C.sub.2 H.sub.5                                                                         CH.sub.3  CH.sub.3                       43     C.sub.2 H.sub.5                                                                   C.sub.3 H.sub.5                                                                       C.sub.4 H.sub.9                                                                       C.sub.6 H.sub.5                                                                         CH.sub.3  CH.sub.3 O                     44     Br  Cl.sub.2 CH                                                                           CH.sub.3                                                                              C.sub.4 H.sub.9                                                                         C.sub.4 H.sub.9                                                                         H                              45     NO.sub.2                                                                          C.sub.5 H.sub.11                                                                      C.sub.3 H.sub.7                                                                       4-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2                                                     4-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2                                                     Br                             46     C.sub.4 H.sub.9 O                                                                 BrCH.sub.2                                                                            CH.sub.3                                                                              4-NO.sub.2 C.sub.6 H.sub.4 CH.sub.2                                                     CH.sub.3  NO.sub.2                       47     H   3-BrC.sub.2 H.sub.4                                                                   C.sub.6 H.sub.4 CH.sub.2                                                              CH.sub.3  C.sub.6 H.sub.5                                                                         C.sub.4 H.sub.9                48     CH.sub.3                                                                          2-BrC.sub.2 H.sub.4                                                                   CH.sub.3                                                                              3-ClC.sub.6 H.sub.4 CH.sub.2                                                            C.sub.2 H.sub. 5                                                                        CH.sub.3                       49     CH.sub.3 O                                                                        3-ClC.sub.3 H.sub.6                                                                   C.sub.4 H.sub.9                                                                       C.sub.4 H.sub.9                                                                         C.sub.4 H.sub.9                                                                         C.sub.2 H.sub.5 O              50     F   2-(C.sub.2 H.sub.5)C.sub.3 H.sub.6                                                    CH.sub.3                                                                              C.sub.2 H.sub.5                                                                         3-BrC.sub.6 H.sub.4 CH.sub.2                                                            C.sub.3 H.sub.7                51     NO.sub.2                                                                          5-BrC.sub.5 H.sub.10                                                                  C.sub.2 H.sub.5                                                                       2,4-Cl.sub.2 C.sub.6 H.sub.3 CH.sub.2                                                   CH.sub.3  F                              52     C.sub.3 H.sub.7                                                                   C.sub.11 H.sub.23                                                                     CH.sub.3                                                                              C.sub.2 H.sub.5                                                                         2,3-(CH.sub.3).sub.2 C.sub.6 H.sub.3                                          CH.sub.2  NO.sub.2                       53     C.sub.2 H.sub.5 O                                                                 C.sub.3 H.sub.5                                                                       C.sub.3 H.sub.7                                                                       2,5-(CH.sub.3).sub.2 C.sub.6 H.sub.3 CH.sub.2                                           C.sub.2 H.sub.5                                                                         CH.sub.3                       54     I   4-C.sub.4 H.sub.9 OC.sub.6 H.sub.4                                                    CH.sub.3                                                                              2,6-Cl.sub.2 C.sub.6 H.sub.3 CH.sub.2                                                   CH.sub.3  H                              55     H   4-C.sub.4 H.sub.9 C.sub.6 H.sub.4                                                     C.sub.6 H.sub.5                                                                       2-FC.sub.6 H.sub.4 CH.sub.2                                                             C.sub.4 H.sub.9                                                                         C.sub.4 H.sub.9 O              56     CH.sub.3                                                                          2,4-Cl.sub.2 C.sub.6 H.sub.3                                                          CH.sub.3                                                                              2-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2                                                     2-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2                                                     H                              57     CH.sub.3 O                                                                        3,5-(CH.sub.3 O).sub.2 C.sub.6 H.sub.3                                                4-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2                                                   4-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2                                                     C.sub.2 H.sub.5                                                                         Br                             58     Cl  3,5-(NO.sub.2).sub.2 C.sub.6 H.sub.3                                                  4-ClC.sub.6 H.sub.4 CH.sub.2                                                          C.sub.2 H.sub.5                                                                         C.sub.2 H.sub.5                                                                         C.sub.2 H.sub.5                59     NO.sub.2                                                                          2-IC.sub.6 H.sub.4                                                                    3-NO.sub.2 C.sub.6 H.sub.4 CH.sub.2                                                   CH.sub.3  CH.sub.3  C.sub.4 H.sub.9                __________________________________________________________________________

What is claimed is:
 1. A substrate for use in electrochromic recordingcomprising a support sheet containing as a color-forming substance a1/2-R-3-[N(R¹ -CO)-N-R² -amino]-7-[N-(R³)(R⁴)-amino]-8/9-R⁵ -10-(R¹-CO)-phenothiazine having the formula ##STR12## wherein: R and R⁵independently represent hydrogen, non-tertiary C₁ to C₄ alkyl,non-tertiary C₁ to C₄ alkoxy, halogen or nitro;R¹ represents hydrogen,non-tertiary C₁ to C₁₂ alkyl, C₄ to C₈ cycloalkyl, non-tertiary C₁ to C₄alkoxy or non-tertiary C₁ to C₄ alkoxycarbonyl, phenyl, phenylsubstituted by one to three of non-tertiary C₁ to C₄ alkyl, non-tertiaryC₁ to C₄ alkoxy, nitro, halo, phenyl, cyano, or trihalomethyl; R²represents C₁ to C₄ alkyl, phenyl, phenyl substituted by one or two ofhalo, nitro, non-tertiary C₁ to C₄ alkyl or non-tertiary C₁ to C₄alkoxy, benzyl or benzyl substituted in the benzene ring by one or twoof halo, nitro, non-tertiary C₁ to C₄ alkyl or non-tertiary C₁ to C₄alkoxy; and R³ and R⁴ independently represent C₁ to C₄ alkyl, phenyl,phenyl substituted by one or two of halo, nitro, non-tertiary C₁ to C₄alkyl or non-tertiary C₁ to C₄ alkoxy, benzyl or benzyl substituted inthe benzene ring by one or two of halo, nitro, non-tertiary C₁ to C₄alkyl or non-tertiary C₁ to C₄ alkoxy.
 2. A substrate for use inelectrochromic recording according to claim 1 comprising a support sheetcontaining as a color-forming substance3-(N-acetyl-N-methylamino)-7-(dimethylamino)-10-acetylphenothiazine. 3.A substrate for use in electrochromic recording according to claim 1comprising a support sheet containing as a color-forming substance3-[N-(4-methoxyphenylcarbonyl)-N-methylamino]-7-(dimethylamino)-10-(4-methoxyphenylcarbonyl)phenothiazine.4. A substrate for use in electrochromic recording according to claim 1comprising a support sheet containing as a color-forming substance3-(N-propylcarbonyl-N-methylamino)-7-(dimethylamino)-10-propylcarbonylphenothiazine.5. A substrate for use in electrochromic recording according to claim 1comprising a support sheet containing as a color-forming substance3-[N-(4-methylphenylcarbonyl)-N-methylamino]-7-(diethylamino)-10-(4-methylphenylcarbonyl)-phenothiazine.6. A substrate for use in electrochromic recording according to claim 1comprising a support sheet containing as a color-forming substance2-methyl-3-(N-acetyl-N-methylamino)-7-(dimethylamino)-10-acetylphenothiazine.7. A substrate for use in electrochromic recording according to claim 1comprising a support sheet containing as a color-forming substance3-(N-acetyl-N-methylamino)-7-(dibutylamino)-10-acetylphenothiazine.
 8. Asubstrate for use in electrochromic recording comprising a support sheetcontaining as a color-forming substance a 1/2-R-3-[N-(R¹ -CO)-N-R²-amino]-7-[N-(R³)(R⁴)-amino]-8/9-R⁵ -10-(R¹ -CO)-phenoxazine having theformula ##STR13## wherein: R and R⁵ independently represent hydrogen,non-tertiary C₁ to C₄ alkyl, non-tertiary C₁ to C₄ alkoxy, halogen ornitro;R¹ represents hydrogen, non-tertiary C₁ to C₁₂ alkyl, C₄ to C₈cycloalkyl, non-tertiary C₁ to C₄ alkoxy or non-tertiary C₁ to C₄alkoxycarbonyl, phenyl, phenyl substituted by one to three ofnon-tertiary C₁ to C₄ alkyl, non-tertiary C₁ to C₄ alkoxy, nitro, halo,phenyl, cyano, or trihalomethyl; R² represents C₁ to C₄ alkyl, phenyl,phenyl substituted by one or two of halo, nitro, non-tertiary C₁ to C₄alkyl or non-tertiary C₁ to C₄ alkoxy, benzyl or benzyl substituted inthe benzene ring by one or two of halo, nitro, non-tertiary C₁ to C₄alkyl or non-tertiary C₁ to C₄ alkoxy; and R³ and R⁴ independentlyrepresent C₁ to C₄ alkyl, phenyl, phenyl substituted by one or two ofhalo, nitro, non-tertiary C₁ to C₄ alkyl or non-tertiary C₁ to C₄alkoxy, benzyl or benzyl substituted in the benzene ring by one or twoof halo, nitro, non-tertiary C₁ to C₄ alkyl or non-tertiary C₁ to C₄alkoxy.